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Jordan R, Maisuls I, Nair SS, Dietzek-Ivanšić B, Strassert CA, Klein A. Enhanced luminescence properties through heavy ancillary ligands in [Pt(C^N^C)(L)] complexes, L = AsPh 3 and SbPh 3. Dalton Trans 2023. [PMID: 38013458 DOI: 10.1039/d3dt03225f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2023]
Abstract
In the frame of our research aiming to develop efficient triplet-emitting materials, we are exploring the concept of introducing additional heavy atoms into cyclometalated transition metal complexes to enhance intersystem-crossing (ISC) and thus triplet emission through increased spin-orbit coupling (SOC). In an in-depth proof-of-principle study we investigated the double cyclometalated Pt(II) complexes [Pt(C^N^C)(PnPh3)] (HC^N^CH = 2,6-diphenyl-pyridine (H2dpp) or dibenzoacridine (H2dba); Pn = pnictogen atoms P, As, Sb, or Bi) through a combined experimental and theoretical approach. The derivatives containing Pn = P, As, and Sb were synthesised and characterised comprehensively using single crystal X-ray diffraction (scXRD), UV-vis absorption and emission spectroscopy, transient absorption (TA) spectroscopy and cyclic voltammetry (CV). Across the series P < As < Sb, a red-shift is observed concerning absorption and emission maxima as well as optical and electrochemical HOMO-LUMO gaps. Increased photoluminescence quantum yields ΦL and radiative rates kr from mixed metal-to-ligand charge transfer (MLCT)/ligand centred (LC) triplet states are observed for the heavier homologues. Transient absorption spectroscopy showed processes in the ps range that were assigned to the population of the T1 state by ISC. The heavy PnPh3 ancillary ligands are found to enhance the emission efficiency due to both higher Pt-Pn bond strength and stronger SOC related to increased MLCT character of the excited states. The experimental findings are mirrored in hybrid (TD-)DFT calculations. This allowed for extrapolation to the rather elusive Bi derivatives, which were synthetically not accessible. This shortcoming is attributed to the transmetalation of phenyl groups from BiPh3 to Pt, as supported by experimental NMR/MS as well as DFT studies.
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Affiliation(s)
- Rose Jordan
- University of Cologne, Faculty for Mathematics and Natural Sciences, Department of Chemistry, Institute for Inorganic Chemistry, Greinstrasse 6, D-50939 Köln, Germany.
| | - Iván Maisuls
- Universität Münster, Institut für Anorganische und Analytische Chemie, CiMIC, CeNTech, Heisenbergstraße 11, D-48149 Münster, Germany.
| | - Shruthi S Nair
- Friedrich Schiller University Jena, Institute for Physical Chemistry (IPC), Helmholtzweg 4, 07743 Jena, Germany.
- Leibniz Institute for Photonic Technologies Jena (IPHT), Research Department Functional Interfaces, Albert-Einstein-Str. 9, 07745 Jena, Germany.
| | - Benjamin Dietzek-Ivanšić
- Friedrich Schiller University Jena, Institute for Physical Chemistry (IPC), Helmholtzweg 4, 07743 Jena, Germany.
- Leibniz Institute for Photonic Technologies Jena (IPHT), Research Department Functional Interfaces, Albert-Einstein-Str. 9, 07745 Jena, Germany.
| | - Cristian A Strassert
- Universität Münster, Institut für Anorganische und Analytische Chemie, CiMIC, CeNTech, Heisenbergstraße 11, D-48149 Münster, Germany.
| | - Axel Klein
- University of Cologne, Faculty for Mathematics and Natural Sciences, Department of Chemistry, Institute for Inorganic Chemistry, Greinstrasse 6, D-50939 Köln, Germany.
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A comprehensive overview on the synthesis, structures and applications of mono-nuclear transition metal complexes with asymmetrically substituted ‘salen-type’ Schiff bases. Inorganica Chim Acta 2023. [DOI: 10.1016/j.ica.2022.121246] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Unprecedented bi- and trinuclear palladium(II)-sodium complexes from a salophen-type Schiff base: Synthesis, characterization, thermal behavior, and in vitro biological activities. J Mol Struct 2023. [DOI: 10.1016/j.molstruc.2022.134224] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Chen K, Hussain M, Razi SS, Hou Y, Yildiz EA, Zhao J, Yaglioglu HG, Donato MD. Anthryl-Appended Platinum(II) Schiff Base Complexes: Exceptionally Small Stokes Shift, Triplet Excited States Equilibrium, and Application in Triplet-Triplet-Annihilation Upconversion. Inorg Chem 2020; 59:14731-14745. [PMID: 32864961 DOI: 10.1021/acs.inorgchem.0c01932] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Two anthryl platinum(II) N,N'-bis(3,5-di-tert-butylsalicylidene)-1,2-benzenediamine Schiff base complexes were synthesized, with the anthryl attached via its 9 position (Pt-9An) or 2 position (Pt-2An) to the platinum (Pt) Schiff base backbone. The complexes show unusually small Stokes shifts (0.23 eV), representing a very small energy loss for the photoexcitation/intersystem crossing process, which is beneficial for applications as triplet photosensitizers. Phosphorescence of the Pt(II) coordination framework (ΦP = 11.0%) is quenched in the anthryl-containing complexes (ΦP = 4.0%) and shows a biexponential decay (τP = 3.4 μs/87% and 18.2 μs/13%) compared to the single-exponential decay of the native Pt(II) Schiff base complex (τP = 3.7 μs). Femtosecond/nanosecond transient absorption spectroscopy suggests an equilibrium between triplet anthracene (3An) and triplet metal-to-ligand charge-transfer (3MLCT) states, with the dark 3An state slightly lower in energy (1.96 eV for Pt-9An and 1.90 eV for Pt-2An) than the emissive 3MLCT state (1.97 eV for Pt-9An and 1.91 eV for Pt-2An). Intramolecular triplet-triplet energy transfer (TTET) and reverse TTET take 4.8 ps/444 ps for Pt-9An and 55 ps/1.7 ns for Pt-2An, respectively. The triplet-state equilibrium extends the triplet-state lifetime of the complexes to 103 μs (Pt-2An) or 163 μs (Pt-9An), in comparison to the native Pt(II) complex, which shows a lifetime of 4.0 μs. The complexes were used for triplet-triplet-annihilation upconversion with perylene as the triplet acceptor. The upconversion quantum yield is up to 15%, and a large anti-Stokes shift (0.75 eV) is achieved by excitation into the singlet metal-to-ligand charge-transfer absorption band (589 nm) of the complexes (anti-Stokes shift is 0.92 eV with 9,10-diphenylanthracene as the acceptor).
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Affiliation(s)
- Kepeng Chen
- State Key Laboratory of Fine Chemicals, School of Chemical Engineering, Dalian University of Technology, E-208 West Campus, 2 Ling Gong Road, Dalian 116024, P. R. China
| | - Mushraf Hussain
- State Key Laboratory of Fine Chemicals, School of Chemical Engineering, Dalian University of Technology, E-208 West Campus, 2 Ling Gong Road, Dalian 116024, P. R. China
| | - Syed S Razi
- State Key Laboratory of Fine Chemicals, School of Chemical Engineering, Dalian University of Technology, E-208 West Campus, 2 Ling Gong Road, Dalian 116024, P. R. China.,Department of Chemistry, Gaya College, Gaya, Constituent Unit of Magadh University, Bodhgaya, Bihar 823001, India
| | - Yuqi Hou
- State Key Laboratory of Fine Chemicals, School of Chemical Engineering, Dalian University of Technology, E-208 West Campus, 2 Ling Gong Road, Dalian 116024, P. R. China
| | - Elif Akhuseyin Yildiz
- Department of Engineering Physics, Faculty of Engineering, Ankara University, Bes̨evler, Ankara 06100, Turkey
| | - Jianzhang Zhao
- State Key Laboratory of Fine Chemicals, School of Chemical Engineering, Dalian University of Technology, E-208 West Campus, 2 Ling Gong Road, Dalian 116024, P. R. China
| | - Halime Gul Yaglioglu
- Department of Engineering Physics, Faculty of Engineering, Ankara University, Bes̨evler, Ankara 06100, Turkey
| | - Mariangela Di Donato
- European Laboratory for Non-Linear Spectroscopy, via North Carrara 1, Sesto Fiorentino, Florence 50019, Italy.,ICCOM-CNR via Madonna del Piano 10, Sesto Fiorentino, Florence 50019, Italy
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Miroslaw B. Homo- and Hetero-Oligonuclear Complexes of Platinum Group Metals (PGM) Coordinated by Imine Schiff Base Ligands. Int J Mol Sci 2020; 21:E3493. [PMID: 32429112 PMCID: PMC7278988 DOI: 10.3390/ijms21103493] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Revised: 05/12/2020] [Accepted: 05/13/2020] [Indexed: 11/16/2022] Open
Abstract
Chemistry of Schiff base (SB) ligands began in 1864 due to the discovery made by Hugo Schiff (Schiff, H., Justus Liebigs Ann. der Chemie 1864, 131 (1), 118-119). However, there is still a vivid interest in coordination compounds based on imine ligands. The aim of this paper is to review the most recent concepts on construction of homo- and hetero-oligonuclear Schiff base coordination compounds narrowed down to the less frequently considered complexes of platinum group metals (PGM). The combination of SB and PGM in oligonuclear entities has several advantages over mononuclear or polynuclear species. Such complexes usually exhibit better electroluminescent, magnetic and/or catalytic properties than mononuclear ones due to intermetallic interactions and frequently have better solubility than polymers. Various construction strategies of oligodentate imine ligands for coordination of PGM are surveyed including simple imine ligands, non-innocent 1,2-diimines, chelating imine systems with additional N/O/S atoms, classic N2O2-compartmental Schiff bases and their modifications resulting in acyclic fused ligands, macrocycles such as calixsalens, metallohelical structures, nano-sized molecular wheels and hybrid materials incorporating mesoionic species. Co-crystallization and formation of metallophilic interactions to extend the mononuclear entities up to oligonuclear coordination species are also discussed.
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Affiliation(s)
- Barbara Miroslaw
- Department of General and Coordination Chemistry and Crystallography, Institute of Chemical Sciences, Faculty of Chemistry, Maria Curie-Sklodowska University in Lublin, Pl. Marii Curie-Sklodowskiej 3, 20-031 Lublin, Poland
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Wu Q, Tang Y, Zi Q. Synthesis, crystallographic structure, Hirshfeld surface analysis and DFT calculations of two salen-type halogenated Schiff-base Ni(II) complexes. Polyhedron 2019. [DOI: 10.1016/j.poly.2019.03.021] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Houjou H, Ikedo H, Yoshikawa I. Single-crystal UV-vis spectroscopic examination of a striking odd-even effect on structure and chromic behaviour of salicylidene alkylamines. Chem Commun (Camb) 2018; 53:10898-10901. [PMID: 28926041 DOI: 10.1039/c7cc06268k] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We have found that a series of N-(5-bromosalicylidene) alkylamines exhibited distinct chromic behaviour depending on the parity of their alkyl chain length. A group with an even number of carbon atoms in the alkyl chain showed photochromism, while another group with odd number showed thermochromism.
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Affiliation(s)
- Hirohiko Houjou
- Institute of Industrial Science, The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8505, Japan.
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